LOW FREQUENCY DRYING OF TRANSFORMER WINDINGS

Before filling a transformer with oil, it is necessary to dry the insulation materials of residual moisture; to apply this process to transformer windings it is possible to use low frequency drying system.
By means of low frequency tension it is possible to warm up short-circuited transformer windings thanks to Joule effect; this means that a high intensity is achieved without applying high tensions, thus allowing a fast, efficient, economic and safe curing of transformer windings.
The main feature of the system is the capacity of warming up the total volume of the windings at once very homogeneously; the warming speed remarkably reduces the time required for the treatment. This also improves the final quality of the dried components as well as the uniform polymerization of the resin used on Diamond Dot Paper (DDP). The use of low frequency drying combined with diamond dot paper also improves the final winding compactness as the uniform warming up also allows the uniform melting of the resin.
If compared with a traditional hot-air system, it can be pointed out that the main advantage is the reduction of drying time; the hot air system has, in fact, to warm up a large volume of air, thus implying a great energy waste. The reduced warming up times achieved with the use of low frequency system also imply that the energy consumption of the system is very low.
The resulting transformer will feature an improved insulation efficiency due to the uniform drying of the active part achieved by means of low frequency system; on larger transformers, also a reduction of the partial discharge levels is achieved.

For more information about low frequency drying click HERE, or contact us directly to get a commercial offer.